Mainstay Energy is a private company offering customers who install, or have installed, renewable energy systems the opportunity to sell the green tags (also known as renewable energy credits, or RECs) associated with the energy generated by these systems. These green tags will be brought to market as Green-e* certified products. Through the Mainstay Energy Rewards Program, participating customers receive regular, recurring payments.

The amount of the payments depends on the type of renewable energy technology, the production of electricity by that system, and the length of the contract period. Mainstay offers 3-, 5-, and 10-year purchase contracts. The longer the contract period, the greater the incentive payment on a $/kWh basis. Payments are made quarterly.

There is a $100 Certification Fee to get started with Mainstay Rewards. This fee does not need to be paid in cash; the fee may be paid with future green tag sales. However, this fee is generally waived for participants who opt for the 10-year contract.

The requirements are:

1. The system must be grid-connected, but does not need to be a net "exporter" of electricity;
2. This incentive is available in addition to any net metering agreement with the utility;
3. The system owner must still have title to the green tags, or renewable energy credits. They cannot have been sold or transferred to any other entity;
4. The system must be a new renewable, which in most states means powered up on or after 1/1/1999. This date is different in some states, see the Mainstay Energy web site for exceptions;
5. The system generation must be metered separately for any systems over 10kW. For systems under 10kW, separate metering is not necessary. Payments are made based on estimated production.

Mainstay Energy is the first company in the U.S. to purchase green tags from small-scale renewable producers on a national scale. The Mainstay Rewards Program currently has about 200 participants -- both commercial and residential.